Process for adjusting the fit of and repairing dentures

ABSTRACT

This invention relates to a process for adjusting the fit of dentures to the mouth when such adjustment is necessitated by changes in the shape of the jaw as a result of aging. The process is also suitable for repair of dentures which have been broken. The process involves the spraying of the denture with a catalyst solution followed by application of a synthetic polymer dissolved in the corresponding monomer which hardens in a short period of time, while in contact with the mouth. As a result, adjustment takes place and a perfect fit between the denture and the mouth is achieved.

United States Patent [1 1 Hofacker et al.

[451 July 17,1973

[ PROCESS FOR ADJUSTING THE FIT OF AND REPAIRING DENTURES [75] Inventors: Erick Hofacker; Frauke Hofacker,

nee Schulter, both of Lubeck, Germany [73] Assignee: Etablissement Rivolan, Schaan, Liechtenstein [22] Filed: Sept. 9, 1970 [21] Appl. No.: 70,909

[52] US. Cl. 32/2 [51] Int. Cl. A61c 13/00 [58] Field of Search 32/2, 8; 18/851 [56] References Cited UNITED STATES PATENTS 3,618,213 l1/197l Shepherd et a1 32/2 3,621,575 11/1971 Schneider et a1. 32/2 2,685,133 8/1954 Greene et a]. 32/2 4/1949 Morgan 32/2 Primary Examiner-Robert Peshock AttorneyMichael S. Striker [57] ABSTRACT This invention relates to a process for adjusting the fit of dentures to the mouth when such adjustment is necessitated by changes in the shape of the jaw as a result of aging. The process is also suitable for repair of dentures which have been broken. The process involves the spraying of the denture with a catalyst solution followed by application of a synthetic polymer dissolved in the corresponding monomer which hardens in a short period of time, while in contact with the mouth. As a result, adjustment takes place and a perfect fit between the denture and the mouth is achieved.

11 Claims, N0 Drawings PROCESS FOR ADJUSTING TI-IE FIT OF AND REPAIRING DENTURES BACKGROUND OF THE INVENTION As is known, occasional adjustment or relining of denture plates is made necessary because of the fact that the jaw changes by atrophy. When such changes occur, the suction and adhesion of the denture to the mouth decreases and consequently the exact, tight, snug fit of the denture is no longer assured. Moreover, such a loosening of the denture results in an increased danger of breakage.

To eliminate this danger, the plate must be treated to restore the exact fit. The general technique thus far has been to apply a synthetic resin in a suitable solvent by means of a spatula or a dropper to the appropriate site on the denture. The denture would then be returned to the mouth of the patient and the plate allowed to harden in contact with the jaw while the patient kept his jaws closed. When using this process, mechanical abrasion of the denture was necessary; in other words, a mechanical treatment was necessary so that the added synthetic material would form a close, tight bond with the denture. This process took about -15 minutes.

After the material added to the denture had hardened, the denture was removed from the mouth and the excess material which had been pushed out to the side by closing the jaws was removed by grinding, and other similar processes.

The relining material is available to dentists from suppliers in the form of a powder. It can be converted to a plastic, deformable soft paste by mixing with a solvent in a vessel. In practice, it has the disadvantage that the formulaion of the components of the mixture in the proper proportion is difficult to prepare exactly, due either to the fact that the necessary measuring vessels are not available, or because the mixture may be prepared in haste. In addition, the process of mixing and the subsequent cleaning of the necessary mixing dishes consumes much time so that increased and unnecessary costs ensue, and a considerable portion of the repair material may be wasted. A further loss of time in applying the conventional processes occurs by reason of the fact that the dentist or the dental technician after the step of hardening while in the mouth, must remove the excess material very exactly from the denture by meansof a grinding process.

Finally, in the process of adding the repair materialeither by a dropping technique or application with a spatula, a uniform distribution of the repair material on the denture is never obtained since by this method the repair material does not reach the vertical edges of the denture. Only after insertion of the denture in the mouth and as a result of closing the jaws, does the material rise in the marginal portions of the denture, a method which necessarily must lead to an unsatisfactory result. The disadvantage of the non-uniform application of the repair material is that the denture is apt to break apart at the same region as before.

SUMMARY OF THE INVENTION lt is an object of the present invention to develop a It is still another object of the present invention to reduce the time involved and the quantity of material wasted in relining and repairing dentures by conventional methods.

The objects of the present invention are achieved by spraying a solution of a synthetic polymerizable compound on theportion of the denture needing relining or repair. The material is preferably applied by spray. Pressure is needed to generate the spray since the solution is viscous. It is desirable that the polymerizable compound be self hardening. For best results, the denture if sprayed with a solution of a hardening catalyst in a volatile solvent. After evaporation of the solvent, the polymer which is preferably a solution of polymer in its own monomer is applied, preferably by spraying. but brushing is also possible.

The catalyst may contain a softener. Also, the polymer solution may contain an accelerator which triggers the action of the catalyst. If necessary, a second portion of the hardening catalyst solution may be applied after applying the polymer solution.

The relined or repaired denture is allowed to harden in the closed jaws of the patient.

DESCRIPTION OF THE PREFERED EMBODIMENTS According to the process presented herein, a denture to be relined or repaired is first cleaned. This may be done with a volatile fat-solvent, and any tartar present must be removed mechanically. Conventional roughening of the denture surfaces is not necessary, since as a result of the use of polymerizable monomers and a catalyst, a homogenous union with the denture is achieved.

As a result of operating in accordance with the present invention, the possibility is achieved of application of the repair or backing material in the exact quantity needed and with no real loss of material. This is achieved through adjustment of the spray jets so that the needed material is deposited exactly on the desired portions of the denture. Since the synthetic material is deposited on the denture as a fine spray, it is therefore ensured that the deposited material will adhere inthe desired quantities in the desired regions without any further precautions.

When operating in accordance with the conventional methods, the fact that the composition of the mixture is inexact leads to inexact hardening times. The operator has no possibility'of determining the exact time that it will take for the deposit of material to harden. If he waits too long, it will be possible that he will not be able to remove the denture from the mouth; if it is taken out too soon, then a poor fit results. With respect to the new method of applying the backing material, the composition is preferably so adjusted that the treated denture will harden within two minutes after positioning in the tightly closed jaws. The denture can then be removed from the mouth with no difficulty.

According to a particularly convenient method of carrying out the invention, the portion of the denture to be repaired is first sprayed with a solution of a hardening catalyst for the plastic, after which it is sprayed with a solution containing the material to be polymerized and finally, if necessary, it is sprayed once more with a solution of a catalyst. For'this purpose, the catalyst should be dissolved in a volatile solvent so that the solvent evaporates quickly. According to this technique, the catalyst solution is sprayed on the denture by means of the usual spray equipment while the polymer solution because of its high viscosity, is applied from a tube or from a pressure vessel. With sufficient pressure, the polymerization solution can also be applied by being sprayed.

The catalyst solution should preferably contain a softening agent such as an alkyl glycol phthalate. For this method of operation, it should be dissolved in the corresponding monomer. It is advantageous to use as the backing material a polyacrylate or polymethacrylate or a mixture of these polymers with other acrylic acid esters or methacrylic acid esters which are soluble in monomethyl methacrylate, or mixtures of methylmethacrylate with other co-polymerizable materials. For this purpose, polyvinylchloride, vinylacetate or polyvinylalcohol are appropriate. Small quantities of cross linking monomers such as glycol dimethacrylate may also be used. The quantity of polymer in the backing material can lie between and 40 percent dissolved in the corresponding monomers. The concentration is so selected that an easily flowable solution results, which in any case, can be sprayed out of the pressure apparatus as a fluid mass.

A variety of organic or inorganic peroxides can be used in accordance with known techniques when dissolved in volatile solvents such as methyl acetate, acetone, or methylethyl ketone. To these solutions can be added a solvent such as alkyl glycol phthalate which makes it easier to deposit the prepared material in the form of a fine, thin layer on the body of the denture. The concentration of the catalyst in the solvent can lie between 2 and 40 percent, preferably between 5 and percent.

In all catalyst systems which have a self-hardening action as is the case here (that is a hardening without heat), it is advantageous to use in addition to the initiator, which in the present case is the catalyst, an accelerator or activator which brings about the decomposition of the initiator and thereby the start of the polymerization of the monomer to a polymer. Under some conditions, the polymerization without an activator is too slow, or in any case, requires time periods which are unsuitable for the present objective. Reducing materials are used as accelerators; examples are aliphatic or aromatic sulfinic acids, for example, toluolsulfinic acid, or alkyl-, alkylaryland oxalkylamine: it is preferable to use tertiary amines in the amount of 5-50 percent based on the quantity of peroxide present.

For spraying of the solution, a vessel is used which has a top opening provided with a spring-loaded valve so that the desired spray quantity can be delivered. For spraying, the valve is opened against the spring pressure by means of the hand so that the vessel contents can be freely delivered to the nozzle opening. This type of spray apparatus is widely available.

The following are examples which illustrate the process.

EXAMPLE l A solution containing 10 weight percent of benzoyl peroxide in 90 weight percent of ethyl acetate is sprayed by means of a spray apparatus on the portion of the denture to be repaired. The solvent evaporates in a short time. A solution containing 35 weight percent of polymethyl methacrylate in 63 weight percent of methyl methacrylate and 2 weight percent of n,n-dimethyl-p-toluidine is sprayed in a thin layer on the denture from a pressurized container. Subsequently the denture may, if necessary, be sprayed again with the peroxide solution. After adjustment of the denture to the jaw, the mass hardens in a few minutes.

EXAMPLE 2 As in Example 1, a catalyst solution of 10 weight percent benzoyl peroxide in 90 weight precent of ethylmethyl ketone is first aPplied. As a relining material is used, a solution of 30 weight percent of a copolymer prepared from 80 weight percent of ethyl methacrylate and 20 weight percent of butyl acrylate, in 65 weight percent of methyl methacrylate, 3 weight percent of glycol dimethacrylate and 2 weight percent of n,n-diethanol-p-toluidine.

EXAMPLE 3 A solution of 35 weight percent of benzoyl peroxide in 65 weight percent of dibutyl phthalate is applied in a thin layer by means of a brush on the portion of a denture to be repaired. On this is applied a solution of 35 weight percent of a copolymer of 60 weight percent of methyl methacrylate and 40 weight percent of ethyl acrylate in 65 weight percent of ethyl methacrylate which contains 3 percent of alkyl methacrylate and 2 percent of n,n-dimethyl-p-toluidine. After the mass thickens, additional catalyst solution is applied. The mass hardens within a few minutes after adjusting the denture to the jaw. Other materials which are suitable for dental processes can be used as thinners for the benzoyl peroxides; an example is alkyl-glycol-phthalate.

EXAMPLE 4 The process is carried through as in Example 1. As relining material is used a copolymer of 96 weight percent of methyl methacrylate and 4 weight percent of ethyl acrylate dissolved to the extent of 25 weight percent in weight percent of methyl methacrylate, which contains 0.2 percent p-toluene-sulfinic acid. The mass hardens in a few minutes. instead of p-toluene sulfinic acid, other sulfinic acids such as benzene sulfinic acid can be used.

It is obvious that for carrying out the new processes described above, instead of the catalyst systems already mentioned to be used for polymerization of the methylacrylates or acrylates, derivatives of sulfinic acids, mercaptans, mercaptides, acrylsulfonalkylamines among others, can also be used.

As the investigation to date has shown, when operating by the previously known techniques, some hours are required for completion of the preparation of a dental plate. in contrast, in operating according to the present invention, the entire process of preparation can, be completed in less than a quarter of an hour. A proportional saving in time can be achieved in the repairing of a denture, since the spray material jet can be applied in the exact quantity necessary to the region of the break, and the subsequent steps of the process are reduced to a minimal expenditure of time.

Finally, it can be seen that when operating in accordance with the method of using spray techniques with spray apparatus, so-called temporary substitutes can be prepared immediately following the extraction of a tooth, as a result of which the patient receives a synthetic substitute.

In the conventional process, the patient bites into a suitable plastic mass to make an impression of the remaining teeth and the gums. A replica of the remaining teeth and gums is made from this impression. Then follows the usual applying of a wax plate, embedding the artificial teeth and molding of the denture.

In making a denture according to the process of the present invention, the wax plate is unnecessary. Instead, the artificial teeth are mounted on the replica, and a lining is prepared by spraying onto the teeth and portions of the replicated gums.

This process when carried out to the usual techniques takes about two hours, whereas when operating according to the invention, the time is cut in half.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and. therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A process of reconditioning a denture in order to readapt it to the shape of the gum comprising the steps of a. applying a solution of a hardening catalyst for the compound employed in step (b) to a denture outside the mouth of the patient; then b. applying a viscous but flowable solution of a lining compound which hardens in contact with said catalyst to at least part of said denture so as to form a lining and coating thereon;

c. pressing the denture with thus-coated surface portion against the corresponding part of the gum of the patient while said hardenable lining compound is still in plastic state so as to conform to the shape of the gum, and permitting the compound of the lining material to harden under the action of said hardening catalyst at least initially in the mouth of the patient and in contact with his gum.

2. The process of claim 1 wherein the said catalyst is applied to the denture by spraying.

3. The process of claim 1 wherein the said hardenable lining compound is applied to the denture by spraying a solution thereof.

4. The process of claim 1 where an additional amount of catalyst is applied to said hardenable compound after application of the latter to the denture.

5. The process of claim 1 wherein the said hardenable compound is a polyacrylate or polymethacrylate dissolved in a monomer thereof.

6. The process of claim 5 wherein the said polyacrylate or methacrylate is employed together with a polyvinyl chloride or polyvinyl acetate.

7. The process of claim 1 wherein the said catalyst is benzoyl peroxide.

8. The process of claim 7 wherein the catalyst is applied together with an accelerator.

9. The process of claim 8 wherein the accelerator is selected from the group consisting of n,n-diethanol-ptoluidine, an aryl sulfinic acid, a mercaptan, a mercaptide and an aryl sulfonalkyl amine.

10. A process of preparing a denture comprising the steps of mounting one or more artificial teeth on a replica of the gums and remaining teeth of the wearer and applying a hardenable compound and a catalyst as defined in claim 1 to said artificial teeth.

11. The process of claim 1 wherein said catalyst is benzoyl'peroxide and said hardenable compound is a polyacrylate or a polymethacrylate in solution in a monomer of an acrylate or methacrylate and wherein the catalyst includes an accelerator.

11. The process of claim 1 wherein said catalyst is benzoyl peroxide and said hardenable compound is a polyacrylate or a polymethacrylate in solution in a monomer of an acrylate or methacrylate and wherein the catalyst includes an accelerator.

UNITED STATES PATENT OFFQICEC v. CERTIFICATE CORRECTION Patent No. 3,745,651 Dated July 17, 1973 Inventofls) ERICK HOFACKER, ET. AL,

It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown. below.

On the cover sheet [75] "'Fra 'uke Hofacker, nee Schulter" should read Frauke Hofacker, nee-Schl uter-r Signed anld sealed this 22nd day of January 1974.

(SEAL) Attest:

"EDWARD M. FLETCHER,JR. RENE D. TEGT-MEYER At't'esting Officer Acting Commissioner of-Patents 

2. The process of claim 1 wherein the said catalyst is applied to the denture by spraying.
 3. The process of claim 1 wherein the said hardenable lining compound is applied to the denture by spraying a solution thereof.
 4. The process of claim 1 where an additional amount of catalyst is applied to said hardenable compound after application of the latter to the denture.
 5. The process of claim 1 wherein the said hardenable compound is a polyacrylate or polymethacrylate dissolved in a monomer thereof.
 6. The process of claim 5 wherein the said polyacrylate or methacrylate is employed together with a polyvinyl chloride or polyvinyl acetate.
 7. The process of claim 1 wherein the said catalyst is benzoyl peroxide.
 8. The process of claim 7 wherein the catalyst is applied together with an accelerator.
 9. The process of claim 8 wherein the accelerator is selected from the group consisting of n,n-diethanol-p-toluidine, an aryl sulfinic acid, a mercaptan, a mercaptide and an aryl sulfonalkyl amine.
 10. A process of preparing a denture comprising the steps of mounting one or more artificial teeth on a replica of the gums and remaining teeth of the wearer and applying a hardenable compound and a catalyst as defined in claim 1 to said artificial teeth.
 11. The process of claim 1 wherein said catalyst is benzoyl peroxide and said hardenable compound is a polyacrylate or a polymethacrylate in solution in a monomer of an acrylate or methacrylate and wherein the catalyst includes an accelerator. 